Allocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.llocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.
Definition of roost. 1  1a : a support on which birds restb : a place where winged animals and especially birds customarily roost. 2  2 : a group of birds roosting together.
habitat. n. 1. (Biology) the environment in which an animal or plant normally lives or grows. 2. (Sociology) the place in which a person, group, class, etc, is normally found. [C18: from Latin: it inhabits, from habitÄre to dwell, from habÄre to have].abâ¢iâ¢tat. 1. the natural environment of an organism; place that is natural for the life and growth of an organism: a jungle habitat. 2. the place where one is usu. found. 3. a special environment for living in over an extended period, as an underwater research vessel.